Concentrating Solar Power (CSP) systems utilize mirrors to concentrate the sun's energy onto points or lines. For instance, trough-shaped solar concentrators focus the sun's energy onto a fluid filed tube; the hot fluid is then transferred to a more conventional steam turbine power plant or similar system to generate electricity. One specific and non-limiting example utilizes a trough that is parabolic in a cross section taken in a plane that is normal to the length of the trough. With the assistance of a tracking system, parabolic trough collectors are very efficient as they follow the movement of the sun during the course of a day. For simplicity, the following discussion refers to parabolic troughs and parabolic mirrors. Of course, other suitable shapes are known.
As solar energy collector apparatuses incorporating parabolic type collectors are now being required to satisfy ever-larger energy requirements, they necessarily become physically larger. In some apparatuses, the aggregate collector surface may typically approach thousands of square meters. Consequently, reliable support for the large parabolic mirrors is critical to ensure excellent performance (focus) in varying atmospheric conditions and to guard against mirror breakage. Some of the key issues include overall frame deflection from its own weight, and that of the attached mirrors and wind loads. Prior art frames for solar trough designs relied on steel fabrications and weldments or aluminum extrusions configured and joined using techniques developed in the building construction industry. Such techniques require pre-assembly and transportation of large frame sections, often to locations that are difficult to access, or they require labor intensive assembly of components on-site, often under unfavorable conditions.
U.S. Pat. No. 4,423,719 discloses a parabolic trough solar energy collector that is fabricated without the need for any blind fasteners or blind fastening devices. An integrated parabolic solar energy collector is provided which can be welded or fastened with spot welds, seam welds, rivets, bolts or the like.
U.S. Pat. No. 4,135,493 discloses a parabolic trough solar energy collector including an elongated support with a plurality of ribs secured thereto and extending outwardly therefrom. One surface of the ribs is shaped to define a parabola and is adapted to receive and support a thin reflecting sheet, which forms a parabolic trough-shaped reflecting surface. One or more of the collectors is adapted to be joined end-to-end, and supported for joint rotation to track the sun.
U.S. Patent Application Publication No. 2010/0050560 discloses a parabolic trough solar energy collector frame including a plurality of chords. The frame comprises a plurality of extruded profiles, including chord sleeves, struts and strut end pieces, each chord sleeve having at least one chord sleeve fin, each chord sleeve positioned about one of the chords. The frame comprises a plurality of struts, at least one of the struts having a strut end piece having at least one strut end piece fin that connects with a chord sleeve fin to connect the plurality of chords. The frame comprises a platform supported by the chords and struts, on which the solar mirrors are disposed.
PCT Publication WO 2010/078004 discloses a solar energy collector apparatus comprising a solar collector panel having a parabolic shape, and a base comprising a pair of spaced apart support frames. Each support frame has a parabolic shape, which corresponds to the parabolic shape of the solar collector panel. Spaced apart rollers may be positioned along an upper surface of each support frame to support the solar collector panel. A drive mechanism may be coupled to the solar collector panel for rotation thereof. The solar collector panel may include a pair of spaced apart rollers to ensure that the solar collector panel rotates squarely with respect to the base.
Unfortunately, even in view of the systems that have been discussed in the preceding paragraphs, there still exists a need for a simplified support system and method for use with trough-shaped solar energy concentrators. It would therefore be advantageous to provide a system and a method that overcomes at least some of the limitations of the prior art.